Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <732474b0-12e4-8dc2-d957-d71aeb40e966@microchip.com>
Date:   Wed, 13 Apr 2022 14:40:49 +0200
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101
 Thunderbird/91.7.0
Subject: Re: [PATCH] ARM: dts: at91: sama7g5ek: Align the impedance of the
 QSPI0's HSIO and PCB lines
Content-Language: en-US
To:     Tudor Ambarus <tudor.ambarus@microchip.com>,
        <claudiu.beznea@microchip.com>
CC:     <alexandre.belloni@bootlin.com>, <devicetree@vger.kernel.org>,
        <linux-arm-kernel@lists.infradead.org>,
        <linux-kernel@vger.kernel.org>,
        "Mihai Sain" <mihai.sain@microchip.com>
References: <20220406130505.422042-1-tudor.ambarus@microchip.com>
From:   Nicolas Ferre <nicolas.ferre@microchip.com>
Organization: microchip
In-Reply-To: <20220406130505.422042-1-tudor.ambarus@microchip.com>
Content-Type: text/plain; charset="UTF-8"; format=flowed
Content-Transfer-Encoding: 7bit
Precedence: bulk

On 06/04/2022 at 15:05, Tudor Ambarus wrote:
> The impedance of the QSPI PCB lines on the sama7g5ek is 50 Ohms.
> Align the output impedance of the QSPI0 HSIOs by setting a medium drive
> strength which corresponds to an impedance of 56 Ohms when VDD is in the
> 3.0V - 3.6V range. The high drive strength setting corresponds to an
> output impedance of 42 Ohms on the QSPI0 HSIOs.
> 
> Suggested-by: Mihai Sain <mihai.sain@microchip.com>
> Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>

Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
And queued in "fixes" branch for 5.18.

Thanks, best regards,
   Nicolas

> ---
>   arch/arm/boot/dts/at91-sama7g5ek.dts | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/arm/boot/dts/at91-sama7g5ek.dts b/arch/arm/boot/dts/at91-sama7g5ek.dts
> index 08685a10eda1..8f9643170ba3 100644
> --- a/arch/arm/boot/dts/at91-sama7g5ek.dts
> +++ b/arch/arm/boot/dts/at91-sama7g5ek.dts
> @@ -655,7 +655,7 @@ pinctrl_qspi: qspi {
>   			 <PIN_PB21__QSPI0_INT>;
>   		bias-disable;
>   		slew-rate = <0>;
> -		atmel,drive-strength = <ATMEL_PIO_DRVSTR_HI>;
> +		atmel,drive-strength = <ATMEL_PIO_DRVSTR_ME>;
>   	};
>   
>   	pinctrl_sdmmc0_default: sdmmc0_default {


-- 
Nicolas Ferre